Kamen: Very basically, as a physicist, I would tell you that a Sterling engine is a heat engine which extracts energy from heat and turns it into mechanical work like other heat engines—like the Braden cycle or the Rankine cycle or the Otto cycle or the Diesel cycle. But, it does it as an external combustion device. The fuel that heats the gas inside the engine never goes inside the engine itself. As a consequence, the Sterling thermodynamic cycle allows you to use a much broader range of fuels because they don’t have to be compatible with the inside workings of your engine. They don’t have to be mixed with air in such a ratio as to get the kind of spark ignition or compression ignition that you have in the kinds of engines in cars and trucks. It allowed us to build an engine that could use many, many more different kinds of fuels, particularly ones that would be locally available around the world: anything from olive oil to cow dung to methane gas. And even when it did burn available
A sterling engine is a highly efficient, combustion-less, quiet engine that harnesses the energy produced when a gas (not gasoline) expands and contracts as its temperature changes. Invented by Robert Stirling in 1816 in Scotland, the Stirling, or sterling, engine uses simple gases and natural heat sources, such as sunlight, to regeneratively power the pistons of an engine. Sterling engines are appealing because they require no replenished source of fuel, run silently, and eject no emissions. In the early 1800s, the primary kind of engines were steam engines on boats and trains. These used the reliable technology of heated water that turned to vapor to power transportation, but they occasionally exploded and endangered operators and passengers. Therefore, Stirling invented an engine that was a closed-system with no explosives, no fire, and no steam, for safety and efficiency. He hoped that the sterling engine would be engineered to be strong enough to eventually power ships and locomot